1. Field of the Invention
The present invention relates to a camera with a shake detection function.
2. Related Art Statement
As disclosed in Japanese Unexamined Patent Publication No. 8-82820, conventional cameras having a shake detection function comprising a dedicated module, containing a differential amplifier, an interface IC, and the like, between a shake sensor and a CPU for controlling the camera, wherein the module amplifies the output of the shake sensor, such as a vibratory gyroscope for detecting a shake of the camera. The CPU issues a state setting signal to the module to keep an output signal of the module to within an appropriate range, specifically, to keep amplified shake information signal from saturation. In response to the state setting signal, the module feeds an appropriate analog voltage to the differential amplifier to keep the output signal to within the appropriate range.
In this way, an offset in the output of the shake sensor is apparently canceled, and the detailed shaken state of the camera is observed over a wide range.
Since the device, disclosed in Japanese Unexamined Patent Publication No. 8-82820, requires a plurality of control lines for controlling the module between the dedicated module and the CPU, the hardware structure of the device becomes complicated. The use of the plurality of control lines makes a circuit board bulky, leading to a bulky device.
Each time the state of the module is determined to control the device accordingly, signals are transmitted. Signal transmission takes time. If the signal transmission is too slow, the detection accuracy of the camera shake is degraded. The use of a fast CPU in an attempt to resolve such a problem may increase not only the power consumption but also the cost of the device.
To monitor the state of the module and then to control the module according to the state monitored, a plurality of pieces of information about the module need to be stored in CPU, requiring a larger memory capacity in CPU. A CPU with a large memory capacity is costly. Since the above-described dedicated module is special and not commercially available, it is expensive.